The present invention relates to an HF-tight component carrier for the insertion of the components of electrical and electronic devices, the carrier including two upper module rails and two lower, parallel module rails; two side walls which are screwed to the ends of the module rails; a bottom provided below the lower module rail, and a cover which is detachably fastened to the upper module rails; with the cover supporting two beveled, narrow edge strips, with each of the two upper module rails being provided with a longitudinal groove which is engaged by the edge strips on the fixed cover; and with at least one metallic spring element resting in each longitudinal groove to ensure electrical contact between the module rail and the cover.
The invention is used in component carriers which require a very high shielding effect against exterior electromagnetic influences or into which components are inserted which develop electromagnetic interference fields that must not extend into the environment.
High-frequency-tight component carriers and the means and measures to shield them from and against the exterior are known. The shield of a component carrier comprising a frame assembled of four module rails and two side walls is usually composed of the side walls themselves, a rear wall, a front panel, a bottom and a cover. This results in the construction of a metal housing which is closed on all sides and whose shielding effect depends solely on the quality of the electrical contact the surrounding components make with one another, since separating grooves are unavoidable. Such contact is made by employing fastening screws which are spaced very closely next to one another, with the help of inserted, electrically contacting seals, wire netting or electrically conductive thin packing cords. In this case, the grooves between the housing and those of the shielding elements, which have to be removed frequently for maintenance, cause special problems, since the shielding effect must not deteriorate, even after repeated removal.
It is known to seal the separating groove between a removable metal cover sheet and the profiled rails in a component carrier against high frequencies by inserting a laminar spring strip longitudinally into a partially covered longitudinal groove of the module rails. An edge strip of the metal cover sheet engages an open slot in the longitudinal groove and, as a result, the resilient laminae of the spring element create a series of electrical contacts between the module rail and the cover. The drawback here is that, prior to the assembly of the component carrier, the spring strip can be inserted into its groove only from the side, and the strip must be positioned in the interior of the groove (DE-OS [Unexamined Published German Patent Application] 3,928,461.
A contract spring strip for electromagnetically sealing housing parts of a shielding housing is also known (DE-GM [German Utility Model Patent] 91/06,954), which comprises a plurality of individual contact springs that are connected to one another via separating webs. Each of these contact springs is provided on one side with an inwardly bent edge region which serves to encircle the exterior edge of a housing member, and on the other side it bears a spring hook which is also bent inwardly and engages an opening of a second housing member that is to be pushed on. Contact spring strips configured in such a way are not usable for sealing a removable cover and module rails in a component carrier against high frequencies.
Moreover, a high-frequency-tight housing was proposed in which a spring metal strip is provided as an HF-seal between the lower part of the housing and a cover gripping over it. A U-shaped portion of this metal strip is plugged onto the edge of the cover, and shaped-on spring tongues, bent in the shape of a roof, resiliently engage the space provided for this purpose between the edge of the cover and the side wall of the housing. These spring metal strips are also not usable for the HF-tight construction of component carriers (DE-OS 3,523,770).